Fault Tolerance
Fault tolerance is the ability of a system to continue operating correctly even when faults or failures occur within its components.
“The degree to which a component or system operates as intended despite the presence of hardware or software faults.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Fault Tolerance?
Fault tolerance ensures that software or hardware can detect, isolate, and recover from faults while maintaining acceptable service levels.
Failure handling: Systems continue operating despite certain faults.
Redundancy: Backup components often support fault tolerance.
Testing focus: Verify the system behaves correctly during failures.
Real World Example
A regulated product team is preparing a release where Fault tolerance appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Fault tolerance as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Fault tolerance and similar ideas.
The page becomes useful in practice because Fault tolerance is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Fault tolerance in the context of ISTQB terminology?
Question 2
A tester needs to explain Fault tolerance to a non‑technical stakeholder. Which approach is MOST appropriate?
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